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README.md

InfluxDB Arduino Client

Simple Arduino client for writing and reading data from <![CDATA[]]>InfluxDB<![CDATA[]]>, it doesn't matter whether it is a local server or InfluxDB Cloud. The library supports authentication, secure communication over TLS, batching, automatic retrying on server backpressure and connection failure.

It also allows setting data in various formats, automatically escapes special characters and offers specifying timestamp in various precisions.

Library supports both InfluxDB 2 and InfluxDB 1.

This is a new implementation and the API, original API is still supported.

Supported devices: ESP8266 (2.7+) and ESP32 (1.0.3+).

InfluxDB Arduino Client

Basic code for InfluxDB 2

After <![CDATA[]]>setting up an InfluxDB 2 server<![CDATA[]]>, first define connection parameters and a client instance:

// InfluxDB 2 server url, e.g. http://192.168.1.48:8086 (Use: InfluxDB UI -> Load Data -> Client Libraries)

define INFLUXDB_URL "influxdb-url" // InfluxDB 2 server or cloud API authentication token (Use: InfluxDB UI -> Load Data -> Tokens -> <select token>) define INFLUXDB_TOKEN "token" // InfluxDB 2 organization name or id (Use: InfluxDB UI -> Settings -> Profile -> <name under tile> ) define INFLUXDB_ORG "org" // InfluxDB 2 bucket name (Use: InfluxDB UI -> Load Data -> Buckets) define INFLUXDB_BUCKET "bucket"

// Single InfluxDB instance InfluxDBClient client(INFLUXDBURL, INFLUXDBORG, INFLUXDBBUCKET, INFLUXDBTOKEN);

The next step is adding data. A single row of data is represented by the Point class. It consists of a measurement name (like a table name), tags (which labels data) and fields ( the values to store):

// Define data point in the measurement named 'devicestatus` Point pointDevice("devicestatus"); // Set tags pointDevice.addTag("device", "ESP8266"); pointDevice.addTag("SSID", WiFi.SSID()); // Add data fields pointDevice.addField("rssi", WiFi.RSSI()); pointDevice.addField("uptime", millis());

And finally, write the data to the database:

// Write data client.writePoint(pointDevice);

Complete source code is available in the BasicWrite example.

Data can be seen in the InfluxDB UI immediately. Use the <![CDATA[]]>Data Explorer<![CDATA[]]> or create a <![CDATA[]]>Dashboard<![CDATA[]]>.

Basic code for InfluxDB 1

Using InfluxDB Arduino client for InfluxDB 1 is almost the same as for InfluxDB 2. The only difference is that InfluxDB 1 uses database as classic name for data storage instead of bucket and the server is unsecured by default. There is also a different InfluxDBClient contructor and setConnectionParametersV1 function for setting the security params. Everything else remains the same.

// InfluxDB server url, e.g. http://192.168.1.48:8086 (don't use localhost, always server name or ip address)

define INFLUXDB_URL "influxdb-url" // InfluxDB database name define INFLUXDBDBNAME "database" // Single InfluxDB instance InfluxDBClient client(INFLUXDBURL, INFLUXDBDB_NAME); // Define data point with measurement name 'devicestatus` Point pointDevice("devicestatus"); // Set tags pointDevice.addTag("device", "ESP8266"); pointDevice.addTag("SSID", WiFi.SSID()); // Add data pointDevice.addField("rssi", WiFi.RSSI()); pointDevice.addField("uptime", millis());

// Write data client.writePoint(pointDevice);

Complete source code is available in BasicWrite example

Connecting to InfluxDB Cloud 2

Instead of setting up a local InfluxDB 2 server, it is possible to quickly <![CDATA[]]>start with InfluxDB Cloud 2<![CDATA[]]> with a <![CDATA[]]>Free Plan<![CDATA[]]>.

Connecting an Arduino client to InfuxDB Cloud server requires a few additional steps. InfluxDBCloud uses secure communication (https) and we need to tell the client to trust this connection. Connection parameters are almost the same as above, the only difference is that server URL now points to the InfluxDB Cloud 2, you set up after you've finished creating an InfluxDB Cloud 2 subscription. You will find the correct server URL in InfluxDB UI -> Load Data -> Client Libraries.

//Include also InfluxClould 2 CA certificate

include <InfluxDbCloud.h> // InfluxDB 2 server or cloud url, e.g. https://eu-central-1-1.aws.cloud2.influxdata.com (Use: InfluxDB UI -> Load Data -> Client Libraries) define INFLUXDB_URL "influxdb-url" // InfluxDB 2 server or cloud API authentication token (Use: InfluxDB UI -> Load Data -> Tokens -> <select token>) define INFLUXDB_TOKEN "token" // InfluxDB 2 organization name or id (Use: InfluxDB UI -> Settings -> Profile -> <name under tile> ) define INFLUXDB_ORG "org" // InfluxDB 2 bucket name (Use: InfluxDB UI -> Load Data -> Buckets) define INFLUXDB_BUCKET "bucket"

You need to pass an additional parameter to the client constructor, which is a certificate of the server to trust. The constant InfluxDbCloud2CACert contains the InfluxDB Cloud 2 CA certificate, which is predefined in this library:

// Single InfluxDB instance InfluxDBClient client(INFLUXDBURL, INFLUXDBORG, INFLUXDBBUCKET, INFLUXDBTOKEN, InfluxDbCloud2CACert);

Writing in Batches

InfluxDB client for Arduino can also write data in batches. A batch is simply a set of points that will be sent at once. To create a batch, the client will keep all points until the number of points reaches the batch size and then it will write all points at once to the InfluDB server. This is often more efficient than writing each point separately.

Timestamp

If using batch writes, the timestamp should be employed. Timestamp specifies the time when data was gathered and it is used in the form of a number of seconds (milliseconds, etc) from epoch (1.1.1970) UTC. If points have no timestamp assigned, InfluxDB assigns a timestamp at the time of writing, which could happen much later than the data has been obtained, because the final batch write will happen when the batch is full (or when flush buffer is forced).

InfuxDB allows sending timestamps in various precisions - nanoseconds, microseconds, milliseconds or seconds. The milliseconds precision is usually enough for using on Arduino. The maximum avavailable precision is microseconds. Setting the timestamp to nanoseconds will just add zeroes for microseconds fraction and will not improve timestamp accuracy.

The client has to be configured with a time precision. The default settings is to not use the timestamp, which means that the server will assign a timestamp when the data is written to the database. The setWriteOptions functions allows setting custom WriteOptions params and one of them is write precision:

// Set write precision to milliseconds. Leave other parameters default. client.setWriteOptions(WriteOptions().writePrecision(WritePrecision::MS));

When a write precision is configured, the client will automatically assign the current time to the timestamp of each written point which doesn't have a timestamp assigned.

If you want to manage timestamp on your own, there are several ways to set the timestamp explicitly. - setTime(WritePrecision writePrecision) - Sets the timestamp to the actual time in the desired precision - setTime(unsigned long long timestamp) - Sets the timestamp to an offset since the epoch. Correct precision must be set InfluxDBClient::setWriteOptions. - setTime(String timestamp) - Sets the timestamp to an offset since the epoch. Correct precision must be set InfluxDBClient::setWriteOptions.

The getTime() method allows copying the timestamp between points.

Configure Time

Dealing with timestamps, and also validating server or CA certificate, requires that the device has correctly set the time. This can be done with one line of code:

The configTzTime function starts the time synchronization with NTP servers. The first parameter specifies the timezone information, which is important for distinguishing between UTC and a local timezone and for daylight saving changes. The last two string parameters are the internet addresses of NTP servers. Check <![CDATA[]]>pool.ntp.org<![CDATA[]]> for address of some local NTP servers.

Timezone string details are described at <![CDATA[]]>https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html<![CDATA[]]>. Values for some timezones: - Central Europe: CET-1CEST,M3.5.0,M10.5.0/3 - Eastern: EST5EDT - Japanesse: JST-9 - Pacific Time: PST8PDT

There is also another function for syncing the time, which takes timezone and DST offset. As DST info is set via static offset it will create local time problem when DST change occurs. It's declaration is following:

configTime(long gmtOffsetsec, int daylightOffsetsec, const char* server1, const char* server2 = nullptr, const char* server3 = nullptr);

In the example code it would be:

// Synchronize time with NTP servers // Accurate time is necessary for certificate validaton and writing in batches configTime(3600, 3600, "pool.ntp.org", "time.nis.gov");

Both configTzTime and configTime functions are asynchronous. This means that calling the functions just starts the time synchronization. Time is often not synchronized yet upon returning from call.

There is a helper function timeSync provided with the this library. The function starts time synchronization by calling the configTzTime and waits maximum 20 seconds for time to be synchronized. It prints progress info and final local time to the Serial console. timeSync has the same signature as configTzTime and it is included with the main header file InfluxDbClient.h:

// Synchronize time with NTP servers and waits for completition. Prints waiting progress and final synchronized time to the Serial. // Accurate time is necessary for certificate validion and writing points in batch // For the fastest time sync find NTP servers in your area: https://www.pool.ntp.org/zone/ void timeSync(const char tzInfo, const char ntpServer1, const char* ntpServer2 = nullptr, const char* ntpServer3 = nullptr);

Batch Size

Setting batch size depends on data gathering and DB updating strategy.

If data is written in short periods (seconds), the batch size should be set according to your expected write periods and update frequency requirements. For example, if you would like to see updates (on the dashboard or in processing) each minute and you are measuring a single value (1 point) every 10s (6 points per minute), the batch size should be 6. If it is sufficient to update each hour and you are creating 1 point each minute, your batch size should be 60. The maximum recommended batch size is 200. Maximum batch size depends on the RAM of the device (80KB for ESP8266 and 512KB for ESP32).

In cases where the data should be written in longer periods and gathered data consists of several points, the batch size should be set to the expected number of points to be gathered.

To set the batch size we use WriteOptions object and setWriteOptions function:

// Enable messages batching client.setWriteOptions(WriteOptions().batchSize(10));

Writing the point will add a point to the underlying buffer until the batch size is reached:

// Write first point to the buffer // Buffered write always returns true client.writePoint(point1); // Write second point to the buffer client.writePoint(point2); .. // Write nineth point to the buffer client.writePoint(point9); // Writing tenth point will cause flushing buffer and returns actual write result. if(!client.writePoint(point10)) { Serial.print("InfluxDB write failed: "); Serial.println(client.getLastErrorMessage()); }

In case cases where the number of points is not always the same, set the batch size to the maximum number of points and use the flushBuffer() function to force writing to the database. See Buffer Handling for more details.

Buffer Handling and Retrying

InfluxDB contains an underlying buffer for handling writing in batches and automatic retrying on server backpressure and connection failure.

Its size is controled by the bufferSize param of WriteOptions object:

// Increase buffer to allow caching of failed writes client.setWriteOptions(WriteOptions().bufferSize(50));

The recommended size is at least 2 x batch size.

The state of the buffer can be determined via two functions: - isBufferEmpty() - Returns true if buffer is empty - isBufferFull() - Returns true if buffer is full

A full buffer can occur when there is a problem with the internet connection or the InfluxDB server is overloaded. In such cases, points to write remain in the buffer. When more points are added and connection problem remains, the buffer will reach the top and new points will overwrite older points.

Each attempt to write a point will try to send older points in the buffer. So, the isBufferFull() function can be used to skip low priority points.

The flushBuffer() function can be used to force writing, even if the number of points in the buffer is lower than the batch size. With the help of the isBufferEmpty() function a check can be made before a device goes to sleep:

```cpp // Check whether buffer in not empty if (!client.isBufferEmpty()) { // Write all remaining points to db client.flushBuffer(); }

Other functions for dealing with buffer: - checkBuffer() - Checks point buffer status and flushes if the number of points reaches batch size or flush interval runs out. This is the main function for controlling the buffer and it is used internally. - resetBuffer() - Clears the buffer.

Check SecureBatchWrite example for example code of buffer handling functions. Write Options Writing points can be controlled via WriteOptions, which is set in the setWriteOptions function: | Parameter | Default Value | Meaning | |-----------|---------------|---------| | writePrecision | WritePrecision::NoTime | Timestamp precision of written data | | batchSize | 1 | Number of points that will be written to the database at once | | bufferSize | 5 | Maximum number of points in buffer. Buffer contains new data that will be written to the database and also data that failed to be written due to network failure or server overloading | | flushInterval | 60 | Maximum time(in seconds) data will be held in buffer before points are written to the db | HTTP Options HTTPOptions controls some aspects of HTTP communication and they are set via setHTTPOptions function: | Parameter | Default Value | Meaning | |-----------|---------------|---------| | reuseConnection | false | Whether HTTP connection should be kept open after inital communicaton. Usable for frequent writes/queries. | | httpReadTimeout | 5000 | Timeout (ms) for reading server response | Secure Connection Connecting to a secured server requires configuring the client to trust the server. This is achieved by providing the client with a server certificate, certificate authority certificate or certificate SHA1 fingerprint. Note: HTTPClient in the current ESP32 arduino SDK (1.0.4) doesn't validate the server certificate, so providing a server certificate is not necessary. But it is definitely safer to do it, as it can change in the future. Other limitation of ESP32 arduino SDK (1.0.4) is that WiFiClientSecure doesn't support fingerprint to validate the server certificate. The certificate (in PEM format) or SHA1 fingerprint can be placed in flash memory to save initial RAM: ```cpp // Certificate of Certificate Authority of InfluxData Cloud 2 servers const char InfluxDbCloud2CACert[] PROGMEM = R"EOF( -----BEGIN CERTIFICATE----- MIIGEzCCA/ugAwIBAgIQfVtRJrR2uhHbdBYLvFMNpzANBgkqhkiG9w0BAQwFADCB iDELMAkGA1UEBhMCVVMxEzARBgNVBAgTCk5ldyBKZXJzZXkxFDASBgNVBAcTC0pl cnNleSBDaXR5MR4wHAYDVQQKExVUaGUgVVNFUlRSVVNUIE5ldHdvcmsxLjAsBgNV BAMTJVVTRVJUcnVzdCBSU0EgQ2VydGlmaWNhdGlvbiBBdXRob3JpdHkwHhcNMTgx MTAyMDAwMDAwWhcNMzAxMjMxMjM1OTU5WjCBjzELMAkGA1UEBhMCR0IxGzAZBgNV BAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEYMBYGA1UE ChMPU2VjdGlnbyBMaW1pdGVkMTcwNQYDVQQDEy5TZWN0aWdvIFJTQSBEb21haW4g VmFsaWRhdGlvbiBTZWN1cmUgU2VydmVyIENBMIIBIjANBgkqhkiG9w0BAQEFAAOC AQ8AMIIBCgKCAQEA1nMz1tc8INAA0hdFuNY+B6I/x0HuMjDJsGz99J/LEpgPLT+N TQEMgg8Xf2Iu6bhIefsWg06t1zIlk7cHv7lQP6lMw0Aq6Tn/2YHKHxYyQdqAJrkj eocgHuP/IJo8lURvh3UGkEC0MpMWCRAIIz7S3YcPb11RFGoKacVPAXJpz9OTTG0E oKMbgn6xmrntxZ7FN3ifmgg0+1YuWMQJDgZkW7w33PGfKGioVrCSo1yfu4iYCBsk Haswha6vsC6eep3BwEIc4gLw6uBK0u+QDrTBQBbwb4VCSmT3pDCg/r8uoydajotY uK3DGReEY+1vVv2Dy2A0xHS+5p3b4eTlygxfFQIDAQABo4IBbjCCAWowHwYDVR0j BBgwFoAUU3m/WqorSs9UgOHYm8Cd8rIDZsswHQYDVR0OBBYEFI2MXsRUrYrhd+mb +ZsF4bgBjWHhMA4GA1UdDwEB/wQEAwIBhjASBgNVHRMBAf8ECDAGAQH/AgEAMB0G A1UdJQQWMBQGCCsGAQUFBwMBBggrBgEFBQcDAjAbBgNVHSAEFDASMAYGBFUdIAAw CAYGZ4EMAQIBMFAGA1UdHwRJMEcwRaBDoEGGP2h0dHA6Ly9jcmwudXNlcnRydXN0 LmNvbS9VU0VSVHJ1c3RSU0FDZXJ0aWZpY2F0aW9uQXV0aG9yaXR5LmNybDB2Bggr BgEFBQcBAQRqMGgwPwYIKwYBBQUHMAKGM2h0dHA6Ly9jcnQudXNlcnRydXN0LmNv bS9VU0VSVHJ1c3RSU0FBZGRUcnVzdENBLmNydDAlBggrBgEFBQcwAYYZaHR0cDov L29jc3AudXNlcnRydXN0LmNvbTANBgkqhkiG9w0BAQwFAAOCAgEAMr9hvQ5Iw0/H ukdN+Jx4GQHcEx2Ab/zDcLRSmjEzmldS+zGea6TvVKqJjUAXaPgREHzSyrHxVYbH 7rM2kYb2OVG/Rr8PoLq0935JxCo2F57kaDl6r5ROVm+yezu/Coa9zcV3HAO4OLGi H19+24rcRki2aArPsrW04jTkZ6k4Zgle0rj8nSg6F0AnwnJOKf0hPHzPE/uWLMUx RP0T7dWbqWlod3zu4f+k+TY4CFM5ooQ0nBnzvg6s1SQ36yOoeNDT5++SR2RiOSLv xvcRviKFxmZEJCaOEDKNyJOuB56DPi/Z+fVGjmO+wea03KbNIaiGCpXZLoUmGv38 sbZXQm2V0TP2ORQGgkE49Y9Y3IBbpNV9lXj9p5v//cWoaasm56ekBYdbqbe4oyAL l6lFhd2zi+WJN44pDfwGF/Y4QA5C5BIG+3vzxhFoYt/jmPQT2BVPi7Fp2RBgvGQq 6jG35LWjOhSbJuMLe/0CjraZwTiXWTb2qHSihrZe68Zk6s+go/lunrotEbaGmAhY LcmsJWTyXnW0OMGuf1pGg+pRyrbxmRE1a6Vqe8YAsOf4vmSyrcjC8azjUeqkk+B5 yOGBQMkKW+ESPMFgKuOXwIlCypTPRpgSabuY0MLTDXJLR27lk8QyKGOHQ+SwMj4K 00u/I5sUKUErmgQfky3xxzlIPK1aEn8= -----END CERTIFICATE----- )EOF";

// Fingerprint of Certificate Authority of InfluxData Cloud 2 servers const char InfluxDbCloud2CAFingerprint[] PROGMEM = "9B:62:0A:63:8B:B1:D2:CA:5E:DF:42:6E:A3:EE:1F:19:36:48:71:1F";

InfluxDb 2

There are two ways to set the certificate or fingerprint to trust a server: - Use full param constructor

// InfluxDB client instance with preconfigured InfluxCloud certificate InfluxDBClient client(INFLUXDBURL, INFLUXDBORG, INFLUXDBBUCKET, INFLUXDBTOKEN, InfluxDbCloud2CACert);

Use setConnectionParams function:

// InfluxDB client instance InfluxDBClient client;

void setup() { // configure client client.setConnectionParams(INFLUXDBURL, INFLUXDBORG, INFLUXDBBUCKET, INFLUXDBTOKEN, InfluxDbCloud2CACert); }

InfluxDb 1

Use setConnectionParamsV1 function:

// InfluxDB client instance InfluxDBClient client;

void setup() { // configure client client.setConnectionParamsV1(INFLUXDBURL, INFLUXDBDATABASE, INFLUXDBUSER, INFLUXDBPASSWORD, InfluxDbCloud2CACert); }

Another important prerequisity to sucessfully validate a server or CA certificate is to have properly synchronized time. More on this in Configure Time.

Note: Time synchronization is not required for validating server certificate via SHA1 fingerprint.

Querying

InfluxDB 2 and InfluxDB 1.7+ (with <![CDATA[]]>enabled flux<![CDATA[]]>) uses <![CDATA[]]>Flux<![CDATA[]]> to process and query data. InfluxDB client for Arduino offers a simple, but powerful, way how to query data with query function. It parses response line by line, so it can read a huge responses (thousands data lines), without consuming a lot device memory.

The query returns FluxQueryResult object, which parses response and provides useful getters for accessing values from result set.

The InfluxDB flux query result set is returned in CSV format. In the example below, the first line contains type information and the second column names, and the rest is data:

#datatype,string,long,dateTime:RFC3339,dateTime:RFC3339,dateTime:RFC3339,long,string,string,string,string ,result,table,start,stop,time,value,SSID,field,measurement,device ,result,0,2020-05-18T15:06:00.475253281Z,2020-05-19T15:06:00.475253281Z,2020-05-19T13:07:13Z,-55,667G,rssi,wifistatus,ESP32 ,result,0,2020-05-18T15:06:00.475253281Z,2020-05-19T15:06:00.475253281Z,2020-05-19T13:07:27Z,-54,667G,rssi,wifistatus,ESP32 ,result,0,2020-05-18T15:06:00.475253281Z,2020-05-19T15:06:00.475253281Z,2020-05-19T13:07:40Z,-54,667G,rssi,wifistatus,ESP32 ,result,0,2020-05-18T15:06:00.475253281Z,2020-05-19T15:06:00.475253281Z,2020-05-19T13:07:54Z,-54,667G,rssi,wifistatus,ESP32 ,result,0,2020-05-18T15:06:00.475253281Z,2020-05-19T15:06:00.475253281Z,2020-05-19T13:08:07Z,-55,667G,rssi,wifistatus,ESP32 ,result,0,2020-05-18T15:06:00.475253281Z,2020-05-19T15:06:00.475253281Z,2020-05-19T13:08:20Z,-56,667G,rssi,wifistatus,ESP32

Accessing data using FluxQueryResult requires knowing the query result structure, especially the name and the type of the column. The best practise is to tune the query in the InfluxDB Data Explorer and use the final query with this library.

Browsing thought the result set is done by repeatedly calling the next() method, until it returns false. Unsuccesful reading is distinqushed by a non empty value from the getError() method. As a flux query result can contain several tables, differing by grouping key, use the hasTableChanged() method to determine when there is a new table. Single values are returned using the getValueByIndex() or getValueByName() methods. All row values at once are retreived by the getValues() method. Always call the close() method at the of reading.

A value in the flux query result column, retrieved by the getValueByIndex() or getValueByName() methods, is represented by the FluxValue object. It provides getter methods for supported flux types:

Flux type	Getter	C type
long	getLong()	long
unsignedLong	getUnsignedLong()	unsingned long
dateTime:RFC3339, dateTime:RFC3339Nano	getDateTime()	FluxDateTime
bool	getBool()	bool
double	bool	double
string, base64binary, duration	getString()	String

Calling improper type getter will result in a zero (empty) value.

Check for null (missing) value using the isNull() method.

Use the getRawValue() method for getting the original string form.

// Construct a Flux query // Query will find RSSI for last 24 hours for each connected WiFi network with this device computed by given selector function String query = "from(bucket: \"my-bucket\") |> range(start: -24h) |> filter(fn: (r) => r.measurement == \"wifistatus\" and r._field == \"rssi\""; query += "and r.device == \"ESP32\")"; query += "|> max()";

// Send query to the server and get result FluxQueryResult result = client.query(query); // Iterate over rows. Even there is just one row, next() must be called at least once. while (result.next()) { // Get typed value for flux result column 'SSID' String ssid = result.getValueByName("SSID").getString(); Serial.print("SSID '"); Serial.print(ssid); Serial.print("' with RSSI "); // Get converted value for flux result column 'value' where there is RSSI value long value = result.getValueByName("value").getLong(); Serial.print(value); // Format date-time for printing // Format string according to http://www.cplusplus.com/reference/ctime/strftime/ String timeStr = time.format("%F %T"); Serial.print(" at "); Serial.print(timeStr); Serial.println(); }

// Check if there was an error if(result.getError() != "") { Serial.print("Query result error: "); Serial.println(result.getError()); }

Complete source code is available in QueryAggregated example.

Original API

Initialization

#define INFLUXDBHOST "192.168.0.32" #define INFLUXDBPORT 1337 #define INFLUXDBDATABASE "test" //if used with authentication #define INFLUXDBUSER "user" #define INFLUXDB_PASS "password"

// connect to WiFi Influxdb influx(INFLUXDBHOST); // port defaults to 8086 // or to use a custom port Influxdb influx(INFLUXDBHOST, INFLUXDB_PORT); // set the target database influx.setDb(INFLUXDBDATABASE); // or use a db with auth influx.setDbAuth(INFLUXDBDATABASE, INFLUXDBUSER, INFLUXDBPASS) // with authentication

// To use the v2.0 InfluxDB influx.setVersion(2); influx.setOrg("myOrganization"); influx.setBucket("myBucket"); influx.setToken("myToken"); influx.setPort(8086);

Sending a single measurement

Using an InfluxData object:

// create a measurement object InfluxData measurement ("temperature"); measurement.addTag("device", d2); measurement.addTag("sensor", "dht11"); measurement.addValue("value", 24.0);

// write it into db influx.write(measurement);

Using raw-data

influx.write("temperature,device=d2,sensor=dht11 value=24.0")

Write multiple data points at once

Batching measurements and send them with a single request will result in a much higher performance.

InfluxData measurement1 = readTemperature() influx.prepare(measurement1)

InfluxData measurement2 = readLight() influx.prepare(measurement2) InfluxData measurement3 = readVoltage() influx.prepare(measurement3)

// writes all prepared measurements with a single request into db. boolean success = influx.write();

Troubleshooting

All db methods return status. Value false means something went wrong. Call getLastErrorMessage() to get the error message.

When error message doesn't help to explain the bad behavior, go to the library sources and in the file src/InfluxDBClient.cpp uncomment line 44:

// Uncomment bellow in case of a problem and rebuild sketch

define INFLUXDBCLIENTDEBUG

Then upload your sketch again and see the debug output in the Serial Monitor.

If you couldn't solve a problem by yourself, please, post an issue including the debug output.

Contributing

If you would like to contribute code you can do through GitHub by forking the repository and sending a pull request into the master branch.

License

The InfluxDB Arduino Client is released under the <![CDATA[]]>MIT License<![CDATA[]]>.

Kihun Song / GitHub_HardwareProjects - Files

Files

IMU_mouse / _Examples / MIT mouse / mouse.brd

IMU_mouse / _Examples / MIT mouse / mouse.sch

IMU_mouse / _PCB / schematic.brd

IMU_mouse / _PCB / schematic.sch

InfluxDB Arduino Client

Basic code for InfluxDB 2

define INFLUXDB_URL "influxdb-url"

define INFLUXDB_TOKEN "token"

define INFLUXDB_ORG "org"

define INFLUXDB_BUCKET "bucket"

Basic code for InfluxDB 1

define INFLUXDB_URL "influxdb-url"

define INFLUXDBDBNAME "database"

Connecting to InfluxDB Cloud 2

include <InfluxDbCloud.h>

define INFLUXDB_URL "influxdb-url"

define INFLUXDB_TOKEN "token"

define INFLUXDB_ORG "org"

define INFLUXDB_BUCKET "bucket"

Writing in Batches

Timestamp

Configure Time

Batch Size

Buffer Handling and Retrying

Write Options

HTTP Options

Secure Connection

InfluxDb 2

InfluxDb 1

Querying

Original API

Initialization

Sending a single measurement

Write multiple data points at once

Troubleshooting

define INFLUXDBCLIENTDEBUG

Contributing

License